Of all the ways animals might reach islands to colonize them, boating has long been a controversial option
In a recent letter to the journal Nature, biologist Ellen Censky and colleagues wrote that many critics have considered the idea of animals rafting to islands as "improbable, unobservable and consequently untenable."
So when Censky reported that a contingent of green iguanas rafted 200 miles on a mat of logs and uprooted trees to the Caribbean island of Anguilla, the news made waves--especially for experts in island biodiversity. Fishermen saw the lizards wash up almost a month after Hurricane Luis and Hurricane Marilyn swept the region in September 1995, and the scientists have since verified the arrival of 15 of the creatures. Green iguanas often rest in trees, and Censky speculates that the animals already were in the branches of the trees that were blown into the water. The refugees formed a big enough group to colonize the island, which previously had no green iguanas, and researchers think they identified a pregnant female this year.
Censky is director of the Connecticut State Museum of Natural History at the University of Connecticut in Storrs.